System, method and medium for simulating normal and abnormal medical conditions

ABSTRACT

The present invention provides a system, method and medium for simulating medical conditions to facilitate medical training, that utilizes a roaming device configured to be mobile; a positioning device configured to determine location information of the roaming device; and a computing device configured to receive the location information, compare the location information with a predetermined set of regions, and transmit information indicative of a medical condition when the location information coincides with the predetermined set of regions.

RELATED APPLICATION

This application claims the priority of U.S. Provisional PatentApplication No. 60/621,084, filed on Oct. 25, 2004, which isincorporated herein by reference in its entirety.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSOREDRESEARCH AND DEVELOPMENT

The present invention is supported in part by the Naval Health ResearchCenter through NAVAIR Orlando TSD under contract N61339-03-C-0157. TheGovernment may have certain rights in the invention.

FIELD OF THE INVENTION

The present invention is directed generally to simulating medicalconditions and, more particularly, to transmitting an indication of themedical condition(s) to a recipient to aid in the diagnosis of variousmedical condition(s).

BACKGROUND OF THE INVENTION

To become clinically competent physicians, medical students must developknowledge and skills in many areas of both the art and science ofmedicine. Three areas are emphasized in medical students' early clinicaltraining: doctor-patient communication, eliciting the patient history,and performing the physical exam. Standardized patients (SPs),individuals trained to realistically portray patients, are commonlyemployed to teach and assess medical students in those three areas. Byworking with SPs, students gain the opportunity to learn and practicethe skills of doctor-patient communication, such as eliciting thepatient history, conducting the physical exams, and other clinicalskills in a safe setting. SPs also provide a way to reliably teststudents' clinical skills in a realistic setting, interacting with aperson. The range of clinical problems an SP can portray, however, islimited. They are typically healthy individuals with few or no abnormalphysical findings. While some can be trained to simulate physicalabnormalities (e.g., breathing through one lung, voluntarily increasingblood pressure, etc.), there are many abnormalities they cannotsimulate.

One way to supplement what students learn from SPs is for the studentsto separately learn from and practice on simulators. A variety ofmechanical or computer-based simulators are now used in medicaleducation, including software for testing clinical reasoning anddiagnostic skills, computer simulations of physiological processes, andphysical models for practicing selected procedural skills. For example,a completely virtual SP (e.g., an interactive computer program) has beentried before by Hubal et al., as described in “The Virtual StandardizedPatient,” Medicine Meets Virtual Reality 2000 (J. D. Westwood et al.,eds., IOS Press), who utilized natural language processing and virtualpatients that exhibit emotion in a realistic context to providecompletely automatic yet unscripted training sessions. A key limitationto these simulators is that their users (e.g., medical students) do notinteract with a live person (a patient or SP). Human-computerinteraction brings a different set of psychological concerns than doesthe human-human interaction of a doctor-patient examination. Asignificant level of immersion is needed to overcome the human-computerinteraction aspects so that there is appreciable transfer of trainingwith regard to patient interaction and diagnosis. This level ofimmersion and interactivity has not been reached and may not beachievable in a totally virtual form with today's technology. AugmentingSPs with the ability to simulate abnormal physical findings would expandthe opportunities for students to learn more clinical skills in arealistic setting with a real person (SP) while practicing theirdoctor-patient communication skills.

In addition, there is currently a need for expanding the breadth ofindications associated with known medical conditions that may beportrayed by an SP. For example, with a real or standardized patient, astudent is limited to hearing only the sounds of that single person.Learning a variety of sounds has traditionally required examining manypatients over time, often without direct supervision and feedback.Commercially available recordings of heart and lung sounds exist, butusing them ignores the process of locating the sources of sounds (e.g.,correct placement of the stethoscope) and excludes simultaneousinteractions with a patient.

Augmenting SPs with the capability of portraying patients with anincreased range of medical conditions would make the use of SPs an evenmore valuable teaching tool. The present invention is directed to theseand other important ends.

SUMMARY OF THE INVENTION

The present invention provides a system, method and medium forsimulating medical conditions to facilitate medical training, thatutilizes a roaming device configured to be mobile; a positioning deviceconfigured to determine location information of the roaming device; anda computing device configured to receive the location information,compare the location information with a predetermined set of regions,and transmit information indicative of a medical condition when thelocation information coincides with the predetermined set of regions.

In at least one aspect of the invention, the location of a roamingdevice is determined by a positioning device and transmitted to acomputing device. In some embodiments, a magnetic tracking system isused to determine the location information of the roaming device. Inother embodiments, an optical tracking system is used to determine thelocation information of the roaming device. In other embodiments, sensordevices are used to determine the location information of the roamingdevice. In some embodiments, the positioning device is a sensor placedon a vest worn by the subject being examined. The computing unitcalibrates the location of the roaming device according to theindividual body morphology or physical movements of the subject

The computing unit is connected to a computer, either as a separate unitor comprised within the computer. The computer contains software forcomparing the location of the roaming device with a predetermined set ofregions. When the location information of the roaming device coincideswith the predetermined set of regions, information indicative of amedical condition is transmitted to an output device connected to thecomputer. The output device can be, for example, a stethoscope earpieceor a speaker connected to the computer, and the information indicativeof a medical condition can be, for example, a sound file selected from acomputer data repository. In some embodiments, the sound file can beplayed through the speaker in surround sound to specify the sound sourcelocation to the location of the object. A touch switch on the roamingdevice can control playback of the computer file, such that playbackonly occurs when the roaming device is touching the subject.

In accordance with the invention, information indicative of a medicalcondition is transmitted when the location of the roaming devicecoincides with a predetermined set of regions. Such regions includepositions over the subject's actual heart, lungs, carotid and renalarteries, aorta, and abdomen. Examples of medical conditions that may besimulated using the invention include: bronchitis, heart failure, lungconsolidation, pneumonia, atelectasis, pleural effusion, pneumothorax,chronic obstructive pulmonary disease, emphysema, asthma, healthy lungfunction, mitral valve prolapse, mitral regurgitation, mitral stenosis,pulmonic stenosis, aortic stenosis, aortic regurgitation, ventricularseptal defect, pericarditis, healthy heart function, bowel obstruction,renal artery bruits, normal abdominal function, and carotid arterybruits.

In one aspect of the invention, the roaming device is a stethoscope andthe information indicative of a medical condition is transmitted as asound played through the earpiece of the stethoscope. The sound iseither a naturally occurring sound or a digitally processed or alteredsound. Examples of sounds heard through the stethoscope in accordancewith the invention include normal breath sounds, crackles, wheezes,stridor, pleural rub, normal heart sounds, pathologic splitting,murmurs, clicks, gallops, pericardial friction rub, venous hum, bowelsounds, and bruits.

In yet another aspect of the invention, the roaming device is aspecialized glove configured to transmit information indicative of amedical condition when the location of the glove coincides with apredetermined set of regions. When the glove detects tactile feedback ata predetermined region, a sound corresponding to a medical condition isselected by the computer for playback into the earpiece of a stethoscopeor through a speaker connected to the computer.

The invention also provides a stethoscope comprising an earpiece and aheadpiece, configured to transmit sound indicative of a medicalcondition when the location of the headpiece coincides with apredetermined set of regions. A touch switch on the headpiece of thestethoscope can be used to control the transmission of sound playedthrough the earpiece.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system diagram in accordance with an exemplary embodiment ofthe invention.

FIG. 2 is a system diagram in accordance with an exemplary embodiment ofthe invention.

FIG. 3 illustrates a stethoscope in accordance with an exemplaryembodiment of the invention.

FIG. 4 is a diagram in accordance with an exemplary embodiment of theinvention.

FIG. 5 is a flow diagram illustrating a method in accordance with anexemplary embodiment of the invention.

FIG. 6 is a system diagram in accordance with an exemplary embodiment ofthe invention.

FIG. 7 is a system diagram in accordance with an exemplary embodiment ofthe invention.

DETAILED DESCRIPTION OF THE INVENTION

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to specific embodiments andspecific language will be used to describe the same. It willnevertheless be understood that no limitation of the scope of theinvention is thereby intended, such alteration and further modificationsof the invention, and such further applications of the principles of theinvention as illustrated herein, being contemplated as would normallyoccur to one skilled in the art to which the invention relates. Also, itis to be understood that the phraseology and terminology employed hereinare for the purpose of description and should not be regarded aslimiting.

FIG. 1, generally at 100, is a system diagram of an exemplary embodimentof the invention. Subject 102 may be, for example, an artificial person,such as a mannequin, or a living person, such as a normal patient or astandardized patient. As used herein, a standardized patient (SP) refersto an individual trained to, or who otherwise can, realistically portraya patient. A user examining subject 102 with object 116, such as astethoscope, would not receive an indication of the subject's actualmedical condition through output device 114 (e.g., actual heart beatsounds). Instead, the user receives a transmission of a computer filefrom computer 122 that simulates a medical condition, when roamingtracking device 112 on object 116 is located at a position or a regionassociated with the medical condition (e.g., position 110 in FIG. 1).

In accordance with some embodiments of the invention, low-frequencymagnetic field technology is used to determine the location of roamingtracking device 112 on object 116. Transmitting device 120, stationarytracking device 104, roaming tracking device 112, and computing unit 118provide a system for determining the location of roaming tracking device112 on object 116 with respect to subject 102. Transmitting device 120can be, for example, an electromagnetic field generator, which generateselectromagnetic signals that are transmitted to tracking devices, suchas magnetic sensors, within a known operating radius of device 120. InFIG. 1, stationary tracking device 104 is on subject 102 and roamingtracking device 112 is on object 116, with both tracking devices withinthe operating radius of transmitting device 120. Both stationarytracking device 104 and roaming tracking device 112 are connected tocomputing unit 118. FIG. 1 shows computing unit 118 as a separate deviceconnected to computer 2. Computing unit 118 can also be comprised incomputer 122, as shown in FIG. 2. FIG. 1 also shows that bothconnections from stationary tracking device 104 and roaming trackingdevice 112 to computing unit 118 are connected via communication links.Communication links can be either with a cable, such as a serial cable,USB connection, or standard telephone wire connection, or wireless, suchas Bluetooth, or any other known short distance wireless communicationtechnology. Transmitting device 120, tracking devices 104 and 112, andcomputing unit 118 are available commercially as a singleelectromagnetic tracking system, such as the Polhemus Fastrak (Polhemus,Colchester, Vt.). Other commercially available tracking systems that maybe used in the invention include the Patriot or Liberty from Polhemusand Flock of Birds, MiniBird, Nest of Birds, or PC Birds from AscensionTechnology (Ascension Technology, Milton, Vt.).

The locations of tracking devices 104 and 112 in space are calculated bycomputing unit 118 using signals received by transmitting device 120.For example, roaming tracking device 112 transmits signals indicative ofits position to computing unit 118. Software associated with computingunit 118 then computes the location of roaming tracking device 112.Computing unit 118 similarly computes the location of stationarytracking device 104. Preferably, computing unit 118 provides locationinformation as substantially instantaneous updates of position (e.g., X,Y, and Z Cartesian coordinates) and/or orientation (e.g., azimuth,elevation, and roll). In embodiments of the invention, orientation maybe measured, for example, as direction cosines, Euler angles, orquaternions.

From the location measurements obtained for tracking devices 104 and 112with respect to transmitting device 120, computing unit 118 determinesthe location of tracking devices 104 and 112 with respect to each other.More specifically, the location of roaming tracking device 112 isdetermined with respect to the location of stationary tracking device104 by computing unit 118. Therefore, computing unit 118 determines thelocation of roaming tracking device 112 relative to the reference frameof subject 102. Computing unit 118 thus provides dynamic locationinformation that is generated according to the individual referenceframes of different subjects.

In accordance with various embodiments of the invention, the correctplacement of roaming tracking device 112 on subject 102 correlates withthe generation of feedback indicative of a known medical condition tothe user. Position and orientation measurements of roaming trackingdevice 112 are transmitted from computing unit 118 to computer 122, andtransformed into a computer readable format utilizing any standard,commercially available software devised for making tracking dataavailable for other applications. For example, software such as TRACKD(VRCO, Virginia Beach, Va.) may be used to transform trackingmeasurements of roaming tracking device 112 into a computer readableformat. As shown in FIG. 1, computing unit 118 is connected to computer122 using a cabled connection. This connection may be, for example, aserial cable, USB connection, or standard telephone wire connection. Inanother embodiment, computing unit 118 is connected to computer 122using a wireless connection. This wireless connection may be, forexample, a Bluetooth connection or any other known short distancewireless communication technology.

Computer 122 contains a data repository of computer files. Each file isprogrammed to generate an indication associated with a known medicalcondition. The location of roaming tracking device 112 with respect tosubject 102, as computed by computing unit 118 and transformed intocomputer readable format, is then used by software running on computer122 to determine which computer file, if any, is selected for playbackinto output device 114 connected to computer 122. The computer softwarecompares the location of roaming tracking device 112 on object 116 to apreviously recorded map of predetermined “hot zone” locations (e.g.,regions) on subject 102. A computer file is selected for playback onlywhen the location of roaming tracking device 112 on object 116 is withina predetermined operating radius of a “hot zone.” For example, acomputer file programmed to play a certain sound associated with aspecific heart defect is selected for playback only when roamingtracking device 112 on object 116 is within the predetermined operatingradius of “hot zone” 110 located over the subject's actual heart. Theoperating radius of a “hot zone” depends on its location and on themedical condition being simulated, and can be, for example, about 1inch, or can be determined by one skilled in the art and adjusted forindividual subjects and medical conditions to be simulated.

The computer file selected for playback is transmitted from computer 122to output device 114. Output device 114 can be, for example, astethoscope earpiece or a speaker. In some embodiments, a sound file canbe transmitted in surround sound through the speaker to specify thesound source location to the location of object 116. FIG. 1 shows thatcomputer 122 is connected to output device 114 using a cabledconnection. This connection may be, for example, a serial cable, USBconnection, or standard telephone wire connection. In anotherembodiment, computer 122 is connected to output device 114 using awireless connection. This wireless connection may be, for example, aBluetooth connection or any other known short distance wirelesscommunication technology.

As used herein, a “hot zone” refers to a location on the body of subject102 that triggers the playback of a corresponding computer file. “Hotzone” locations on a subject correspond with one or more simulatedmedical conditions. For example, if a particular cardiovascularcondition is desired to be simulated, one or more “hot zones”corresponding to the particular heart condition will be located, forexample, over the subject's anterior chest and/or major arteries, suchas the carotid or renal artery. As another example, if a particular lungcondition is desired to be simulated, one or more “hot zones”corresponding to the particular lung condition will be located, forexample, over the subject's lungs. Other “hot zones” in accordance withthe invention include areas generally examined by physicians during thepulmonary examination, such as the 26 areas described in Bates' Guide toPhysical Examination and History Taking (Bickley & Szilagyi,Philadelphia: Lippincott William & Wilkons 2003), incorporated byreference in its entirety.

One skilled in the art may also appreciate that the location in space ofa given “hot zone” will vary among subjects. For example, “hot zone”locations may vary depending on the individual subject's body morphologytype (for example, obese v. thin body types or male v. female bodytypes), or if a subject shrugs her shoulders or twists. In one or moreembodiments of the invention, tracking device measurements arerecalibrated to account for these variations and deviations amongdifferent subjects. Position measurements for stationary tracking device104 on subject 102 with respect to transmitting device 120 are comparedby computing unit 118 to position measurements obtained using a frame ofreference as measured, for example, by an tracking device attached to asubject of average height, weight, and build. Any deviations in theposition measurements for stationary tracking device 104 from theneutral position are accordingly subtracted from the positionmeasurements obtained for roaming tracking device 112 on object 116. Insome embodiments, neoprene vests of standard sizes (for example, XS toXXL) labeled with “hot zone” locations and calibration reference pointscan be used for calibrating the system according to any individualsubject's morphological type. The subject can wear a vest of appropriatesize for a short period of calibration to individualize the “hot zone”pattern for the subject.

When the location of roaming tracking device 112 on object 116 is withinthe range of a “hot zone,” a computer file is selected for playback andtransmitted from computer 122 to output device 114. In some embodiments,roaming tracking device may include a touch switch 124. In operation,touch switch 124 enables output device 114. In other words, a user isnot able to detect through output device 114 the playback of theselected computer file unless touch switch 124 is in the “closed”position. Computer 122 transmits the playback of a selected file totouch switch 124, which is connected to output device 114. If touchswitch 124 is in the “open position,” the playback transmission tooutput device 114 is blocked. However, touch switch 124 closes uponcontact with subject 102 into the “closed” position, allowing theplayback transmission to be detected through output device 114 by theuser. Touch switch 124 can be a standard, commercially available SDPTswitch with ¾″ roller lever, such as Radio Shack catalog #275-017,modified by removing the roller from the switch.

FIG. 5 is a flow diagram illustrating the steps performed according toan exemplary embodiment of the invention. At step 310, a coordinatesystem with a reference point is created with a computing device. Thereference point can be, for example, a stationary tracking deviceattached to the subject. At the next step, step 320, “hot zone”locations are mapped within the coordinate system, using informationknown to one of skill as described above. At step 330, the “hot zone”map is stored on the computing device. A roaming tracking device is thenmoved over the subject at step 340. The computing device determines thelocation of the roaming tracking device at step 350, then compares thelocation of the roaming tracking device to the pre-recorded “hot zone”map at step 360. If the location of the roaming tracking device iswithin the range of a “hot zone” at step 370, the computing devicetriggers the playback of sound through an output device, such as astethoscope earpiece or a speaker connected to the computing device, atstep 380. The sound is played continuously as long as the roamingtracking device is within the range of the “hot zone” location.

In one or more embodiments of the invention, object 116 is a standardelectronic stethoscope, such as, generally the Androscope i-stethosmodel IS-28A00 (Andromed, Inc., St. Laurent, Quebec), modified asdescribed herein. FIG. 3 shows an exemplary stethoscope in accordancewith the invention. As shown in FIG. 3, touch switch 124 and roamingtracking device 112 are mounted on headpiece 126 of object 116. Earpiece128 (corresponding to output device 114 in FIG. 1) is a separate devicefrom headpiece 126. In some embodiments of the invention, headpiece 126and earpiece 128 are incorporated in a single device. Earpiece 128 isconnected to the audio output device of computer 122.

Transmission of a computer sound file from computer 122 to earpiece 128correlates with correct placement of headpiece 126 on subject 102. Inone or more embodiments of the invention, the sound file is a .wav file.However, other sound files, such as .mp3 files, may be used. The soundfile may correspond to either a naturally occurring sound (e.g., anormal heartbeat) or to a sound that has been digitally processed (e.g.,modifying a normal heartbeat to sound like an abnormal heartbeat) ordigitally altered (e.g., adding extra sounds to normal heart sounds tosimulate a valvular defect, or adding wheezes to breath sounds tosimulate asthma). Commercially available software for digital signalprocessing may be used in connection with embodiments of the invention.For example, WaveWarp from SoundsLogical (Glasgow, Scotland UK) may beused.

Computer playback of the sound file is timed to correspond to the actualinspiration and expiration of the subject. A sound sensing/modifyingapproach is used where the computer receives input device information onthe subject's inspiration/expiration and adjusts the timing of the lungsounds accordingly. Information on the subject's breathing pattern isobtained using a subject-controlled actuator switch or a plethysmographto monitor chest movement.

FIG. 4 is a diagram of an exemplary embodiment of the invention. A soundfile transmitted to earpiece 128 provides auscultatory feedback to theuser when the user places headpiece 126 on an appropriate “hot zone.”For example, when headpiece 126 is located on “hot zone” position 110over the location of the subject's actual heart, computer 122 may selectsound file C corresponding to “hot zone” 110, generating abnormal soundsassociated with, for example, a heart defect, for playback into earpiece128. Alternatively, when headpiece 126 is located on “hot zone” position110, computer 122 may select sound file D also corresponding to “hotzone” 110, generating normal sounds associated with a normal heart. Aschart 130 illustrates, computer 122 will select sound file A whenheadpiece 126 is located on “hot zone” position 106, and the computerwill select sound file B when headpiece 126 is located on “hot zone”position 108. The sound files selected for playback into the stethoscopecorrespond to sounds commonly auscultated during the physicalexamination of a patient. The auscultation of sounds associated witheither a normal or an abnormal medical condition is used, for example,by a user to make a medical diagnosis regarding the medical condition ofthe subject. As used herein, “auscultation” refers to the act oflistening for sounds made by internal organs, such as the heart, lungs,abdomen, and major arteries, to aid in the medical diagnosis of asubject.

In accordance with the invention, the auscultated sound corresponds tothe particular medical condition that is simulated by the subject. Inone embodiment, a heart condition is simulated by the playback ofheart-associated sounds. Examples of heart-associated sounds that may begenerated, and the associated heart condition that is simulated,include: normal heart sounds, pathologic splitting, murmurs, clicks,gallops, pericardial friction rub, venous hum, and carotid arterybruits, for simulating healthy heart function, heart failure, mitralvalve prolapse, mitral regurgitation, mitral stenosis, pulmonicstenosis, aortic stenosis, aortic regurgitation, ventricular septaldefect, and pericarditis. In another embodiment, a lung condition issimulated by the generation of lung-associated sounds. Examples oflung-associated sounds that may be generated, and the associated lungcondition that is simulated, include: normal breath sounds, crackles,wheezes, stridor, and pleural rub, for simulating healthy lung function,bronchitis, lung consolidation, pneumonia, atelectasis, pleuraleffusion, pneumothorax, chronic obstructive pulmonary disease,emphysema, and asthma. In another embodiment, an abdominal condition issimulated by the generation of abdominal-associated sounds. Examples ofauscultation sounds that may be generated, and the associated abdominalcondition that is simulated, include: bowel sounds and bruits, forsimulating bowel obstruction, renal or aortic artery bruits, and normalabdominal function.

In another embodiment of the invention, an optical tracking system thatutilizes optical motion capture may be used for determining the locationof a roaming device. Optical motion capture is the tracking of markers,such as LED markers, on an object over time. Generally, cameras areplaced on the perimeter of a capture area to track markers placed on theobject. Using an optical tracking system, active marker positions aredetected by camera sensors and transmitted to a central processor, whichcalculates and stores the coordinate positions for the markers. Opticaltracking systems such as ARToolkit (Human Interface TechnologyLaboratory, University of Washington, Seattle, Wash.), PhaseSpaceoptical motion capture systems (PhaseSpace, San Leandro, Calif.),HiBall-3000 (3rdTech, Inc. Chapel Hill, N.C.), Vicon small camerasystems (Vicon Motion Systems, Inc., Lake Forest, Calif.), the HawkSystem (Motion Analysis Corp., Santa Rosa, Calif.), and the Eagle System(Motion Analysis) may be used in conjunction with the invention.

FIG. 6, generally at 400, is a system diagram of an exemplary embodimentof the invention. An optical marker 134 is placed on the user's hand 132or on an object held in the user's hand, such as a stethoscopeheadpiece, while the user performs an examination of the subject 102. Acamera sensor 136, placed within a known operating radius of opticalmarker 134 and connected to computer 122, detects the position in threedimensions of the optical marker 134. Various software associated withcomputer 122 then determines the location of optical marker 134 relativeto the location of camera sensor 136, converts the position measurementsto a computer readable format, and compares the location of opticalmarker 134 to a previously recorded map of predetermined “hot zone”locations on subject 102. When the user taps the back of the subject ona “hot zone” location, for example “hot zone” location 110, a computerfile corresponding to the “hot zone” is transmitted from the computer122 for playback to an output device 138, such as a speaker connected tothe computer or a stethoscope earpiece. In some embodiments, thecomputer file is transmitted for playback to a speaker using surroundsound software to specify the sound source location to the location ofthe user's hand 132. Commercially available software for surround soundbroadcasting may be used in connection with embodiments of theinvention. For example, Maven3D from Emersys (Daejeon, South Korea) maybe used.

In another embodiment of the invention, a specialized glove 140, suchas, generally the CyberTouch or the CyberGlove (Immersion Corp., SanJose, Calif.) is used, at least in part, to simulate a medicalcondition. FIG. 7, generally at 500, is a system diagram showing anexemplary embodiment of the invention. Glove 140 is mounted at the wristportion with roaming tracking device 142, which transmits signalsindicative of its position to computing unit 118. Measurements of theposition of roaming tracking device 142 thus provides the generallocation of glove 140 from the wrist position and a plurality offiberoptic sensors can be embedded in glove 140 to measure the flexionof the fingers. Glove 140 is also connected to computer 122 and iscapable of transmitting various information to the computer. Forexample, when the user taps the back of subject 102 on a “hot zone”location, glove 140 detects the vibrations emanating from the body ofsubject 102 and transmits a signal to computer 122. The signal triggersthe playback of a computer file corresponding to the “hot zone,”transmitted from computer 122 for playback into output device 114 orthrough speaker 138 connected to computer 122. The computer file can be,for example, a sound file transmitted in surround sound through speaker138. In a more specific example, the user may tap the back of subject102 on “hot zone” position 110 over the subject's lungs. Computer 122would correlate the position of glove 140, as determined by computingunit 118, with a sound file that generates echoic or dull lung sounds,for playback into output device 114 or through speaker 138. Variousother sound files can be accessed to simulate different medicalconditions.

In another embodiment of the invention, a sensor system is used todetermine the location of a roaming device. For example, sensing devicesconfigured to detect when a marker moves within an operating radius canbe fastened or mounted to “hot zone” locations on a vest worn by thesubject. When a marker, mounted on a user's hand or on an object such asa stethoscope in the user's hand, is moved within a “hot zone,” thesensing device communicates this information to a computer, and softwareassociated with the computer triggers the playback of a sound filethrough an output device such as a computer speaker or the earpiece ofthe stethoscope. In some embodiments, the sensing device can be used asthe roaming device to detect markers fastened to the “hot zone”locations on the vest. Sensing devices configured to detect markers areknown and readily available to one skilled in the art.

According to one or more embodiments of the invention, the components ofthe system for simulating normal or abnormal medical conditions can beconnected in different ways. For example, the connections can be wired,wireless, optical, electromagnetic, and the like. In addition, one ormore cameras can be used to provide information and/or position data forthe tracking devices. Alternatively, or additionally, tracking devicesor magnetic sensors known in the art can be incorporated into thetracking system to assist in, or detect, the location of the trackingdevice. The functions of one or more devices can also be combined into asingle device. For example, the computer can be programmed, and includeappropriate hardware, to perform the functions of the tracking system.Various components can also be connected across one or more networks sothat data can be exchanged and/or analyzed by others. For example, in aclassroom setting, an instructor can demonstrate the appropriatelocations to position the stethoscope. Appropriate signals can be sentto the computer and transmitted across a wireless network. Users in theclassroom would then receive the appropriate sounds in their ownstethoscopes. All such embodiments, modifications, and variations fallwithin the scope of the present invention.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly the preferred embodiments have been shown and described and thatall changes and modifications that come within the spirit of theinvention are desired to be protected. In addition, all references citedherein are indicative of the level of skill in the art and are herebyincorporated by reference in their entirety.

We claim:
 1. A system for simulating medical conditions to facilitatemedical training, the system comprising: markers to be positioned atlocations on a subject's body, the markers respectively having detectionzones corresponding to a predetermined set of regions; a sensing deviceto detect the markers; and an earpiece to be worn by a user, theearpiece coupled to the sensing device to provide sounds when themarkers are detected, the sounds being representations of soundsproduced by body parts in the predetermined set of regions.
 2. Thesystem of claim 1, wherein the sounds are naturally occurring sounds. 3.The system of claim 1, wherein the sounds are digitally processedsounds.
 4. The system of claim 1, wherein the sounds are altered sounds.5. The system of claim 1, wherein the sounds include at least one of:normal breath sounds, crackles, wheezes, stridor, pleural rub, normalheart sounds, pathologic splitting, murmurs, clicks, gallops,pericardial friction rub, venous hum, bowel sounds, and bruits.
 6. Thesystem of claim 1, wherein the sounds represent a medical condition, themedical condition is at least one of: bronchitis, heart failure, lungconsolidation, pneumonia, atelectasis, pleural effusion, pneumothorax,chronic obstructive pulmonary disease, emphysema, asthma, healthy lungfunction, mitral valve prolapse, mitral regurgitation, mitral stenosis,pulmonic stenosis, aortic stenosis, aortic regurgitation, ventricularseptal defect, pericarditis, healthy heart function, bowel obstruction,renal or aortic artery bruits, normal abdominal function, and carotidartery bruits.
 7. The system of claim 1, wherein the predetermined setof regions comprises regions over the heart, lungs, carotid artery,renal artery, and abdomen of a subject being examined.
 8. The system ofclaim 1, wherein the sensing device is part of a training stethoscopeconfiguration that communicates with a computer.
 9. The system of claim1, wherein the earpiece is a stethoscope earpiece.
 10. The system ofclaim 1, wherein the markers are placed on a vest worn by the subject.11. The system of claim 1, wherein the sensing device and the markersare in short distance wireless communication.
 12. The system of claim 8,wherein the training stethoscope configuration receives signalsindicative of the sounds through wireless communication with thecomputer.
 13. The system of claim 12, wherein the computer contains adata repository of computer files, and wherein the files are programmedto generate an indication associated with a known medical condition. 14.The system of claim 1, wherein the sensing device communicates with acomputing component that assists with providing the sounds.
 15. Thesystem of claim 1, wherein the subject is a human subject.